Cloud point extraction for the determination of copper in environmental samples by flame atomic absorption spectrometry

Abstract

Recebido em 13/12/06; aceito em 5/7/07; publicado na web em 19/12/07 A simple cloud point extraction procedure is presented for the preconcentration of copper in various samples. After complexation by 4-hydroxy-2-mercapto-6-propylpyrimidine (PTU), copper ions are quantitatively extracted into the phase rich in Triton X-114 after centrifugation. Methanol acidified with 0.5 mol L -1 HNO 3 was added to the surfactant-rich phase prior to its analysis by flame atomic absorption spectrometry (FAAS). Analytical parameters including concentrations for PTU, Triton X-114 and HNO 3 , bath temperature, centrifugation rate and time were optimized. The influences of the matrix ions on the recoveries of copper ions were investigated. The detection limits (3SD b /m, n=4) of 1.6 ng mL -1 along with enrichment factors of 30 for Cu were achieved. The proposed procedure was applied to the analysis of environmental samples.

Selective separation, preconcentration and determination of Pd(II) ions in environmental samples by coprecipitation with a 1,2,4-triazole derivative

“…A preconcentration step combined with matrix separation is often required for environmental samples prior to the determination by flame atomic absorption spectrometry (FAAS) [15,16]. The methods developed for this purpose are based on ion exchange [17], membrane filtration [18], solid phase extraction [19], fire-assay [20], cloud point extraction [21], liquid-liquid microextraction [22] and electroanalytical techniques [23].…”

Application of cloud point preconcentration and flame atomic absorption spectrometry for the determination of cadmium and zinc ions in urine, blood serum and water samples

“…17 Thus, there is a growing tendency to use surfactants in trace analysis of organic [18][19][20][21] and inorganic materials. [22][23][24][25][26][27][28][29][30][31][32] However, despite the critical importance of Zn 2+ and Cd 2+ monitoring in many industrial, environmental, clinical and pharmaceutical samples, only a few cases of the use of CPE for the separation and preconcentration of Zn 2+ and Cd 2+ have been reported in the literature. [33][34][35][36] In this work, a cloud-point preconcentration procedure was introduced for determination of Zn 2+ and Cd 2+ ions, after the formation of complex with 3,3',3",3'"-tetraindolyl (terephthaloyl) dimethane (TTDM).…”

Separation and preconcentration of copper in environmental samples on Amberlite XAD-8 resin after complexation with a carbothioamide derivative

“…8,9 Because of these problems, a separation and preconcentration process is necessary for improving the sensitivity of the analytical detection method and for providing low detection limits. Various separation/preconcentration techniques, including solid phase extraction (SPE), 10,11 ion exchange, 12 cloud point extraction, 13 membrane filtration, 14 electroanalytical techniques, 15 and coprecipitation, 16 are used prior to instrumental determination of trace elements. SPE is the most widely used preconcentration technique for the determination of trace elements.…”